change default installation directory for cmake files:

[LocutusOfBorg]

now the default becomes "{CMAKE_INSTALL_LIBDIR}/cmake/cpprestsdk"

This is a respin of #845

[BillyONeal]

Is there anything substantial that has changed since #845 which would warrant a change here? I'm concerned that this is a breaking change.

[c72578]

For the Fedora packages [1] we currently use -DCPPREST_EXPORT_DIR=cmake/cpprestsdk.
This matches the directory suggested by PR #1306 here. So, if the default value for CPPREST_EXPORT_DIR gets updated according to this PR, we could omit -DCPPREST_EXPORT_DIR=cmake/cpprestsdk in the future.

[1] https://src.fedoraproject.org/rpms/cpprest/blob/53defcf55ec147f7ac9b5b96a56e804bf67767e8/f/cpprest.spec#_61

[BillyONeal]

@c72578 I get that, but what about anyone who is not currently passing that switch and are relying on the current layout? I know absolutely nothing about this pkg-config support stuff, so I would not want to merge this unless there's something substantial that changed since #845 where my predecessor (who understands that area much better than I) rejected an identical change.

[LocutusOfBorg]

@BillyONeal #845 was a mistake on my side, because it was forcing people to add CMAKE_INSTALL_LIBDIR in the export directory, unconditionally.
"DESTINATION ${CMAKE_INSTALL_LIBDIR}/${CPPREST_EXPORT_DIR}"

even if this was right, it was a wrong approach, removing the configurability of the full path from maintainer perspective.

Now, since the standard cmake approach is to put stuff in cmake/$SOURCE, this pull request changes the default to that, and BTW I can say that Fedora, Debian, Yocto are already using that standard PATH, so with this PR merged we will just drop the need to explictly change the default and carry a patch.

[LocutusOfBorg]

I'm pretty sure nobody will complain about that change, because the current default can't be found via cmake.

to test this:

cat ../CMakeLists.txt 
cmake_minimum_required(VERSION 3.10)
find_package(cpprestsdk REQUIRED)

cmake ..

and then

//The directory containing a CMake configuration file for cpprestsdk.
cpprestsdk_DIR:PATH=/usr/lib/x86_64-linux-gnu/cmake/cpprestsdk

[BillyONeal]

OK, sounds reasonable. Thanks for your contribution! (And thanks @ras0219-msft for double checking)

[LocutusOfBorg]

Btw please tag me if anybody complains and I'll make sure to find a way that fits everybody's needs